What is a Concussion?
A concussion is an injury to the brain occurring as the result of a traumatic force. The force that causes the injury can occur from a direct blow to the head. The injury can also occur as a result of an indirect force to the head such as when a player is hit in the chest or back by another player. When an individual has suffered a recent sports concussion injury there is typically no structural abnormality of the brain that can be seen on standard imaging. The actual brain injury can only be visualized when brain tissue is viewed through a microscope using special techniques or in some instances with highly specialized imaging equipment.
In caring for patients and educating the public about concussions we typically define concussions by the symptoms patients experience. Possible symptoms of concussion are vast and can look quite similar to many other conditions. Each patient experiences a unique symptom array with a concussion injury. If the same patient experiences more than one concussion, then each concussion is often different in regards to the symptoms experienced. This makes defining a concussion and in some instances diagnosing a concussion challenging.
Our understanding of the effects and symptoms of sports related concussion in the first days and weeks after concussion continue to evolve. As this occurs the definition, symptoms, and evaluation techniques continue to evolve, as well.
As previously described the underlying condition in a sports related concussion is an injury to the brain. This injury affects the way the cells and nerves of the brain communicate and function. The injury is considered to be at the microscopic level impacting cells, axons, and chemical functions of the brain. The injury is often described as an injury that involves a “neurometabolic cascade.” The neurometabolic cascade refers to the disruption of cell metabolism and ion transmitter levels within the brain that occur as a result of the injury.
Athletes in any sport may experience a sports related concussion. Collision and contact sports represent the highest risk. Actual annual rates of sports related concussion are unclear as it is believed that a high number of sports related concussions go unreported.
Factors have been identified that increase risk of a sports related concussion or affect recovery. Currently recognized factors:
- Prior history of concussion – increases risk of new concussion or more prolonged post-concussion recovery
- Female sex – females playing a sport with comparable playing rules and style to the male equivalent have demonstrated increased incidence
- Youth athletes – recovery is more often prolonged and risk of severe complication (eg. bleeding in the brain and brain swelling)
- Preinjury conditions that impact diagnosis, management, and/or recovery;
- Mood disorders, particularly anxiety and depression
- Learning disorders
- Attention Deficit Disorders (ADD, ADHD)
- Migraine headache history